<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        

        // title : '明天放假'
        // obj.title = '明天放假';
        let str = 'title';
        //在对象外添加
        // obj[str] = '明天放假';

        let obj = {
            [str]: '测试'
        }

        console.log(obj);
    </script>
</body>
</html>